Clinicaltrials Search Studies
clinicaltrials_search_studiesRead-onlyIdempotent
Search clinical trials from ClinicalTrials.gov using full-text or field-specific queries. Filter by status, phase, location, and more to find relevant studies.
Instructions
Search for clinical trial studies from ClinicalTrials.gov. Supports full-text and field-specific queries, status/phase/geographic filters, pagination, sorting, and field selection. Use the fields parameter to reduce payload size — full study records are ~70KB each.
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| query | No | General free-text search across all fields. Plain words plus AND, OR, NOT. `[ ]` are reserved (advancedFilter AREA[] only); `( )` group sub-expressions and work when matched; `,` acts as AND. For field-scoped searches, use the dedicated *Query parameters (conditionQuery, interventionQuery, etc.) or advancedFilter with AREA[FieldName]value. | |
| conditionQuery | No | Condition/disease-specific search. E.g., "Type 2 Diabetes", "non-small cell lung cancer". Plain words plus AND/OR/NOT. `[ ]` are reserved; `( )` group sub-expressions when matched; `,` acts as AND. | |
| interventionQuery | No | Intervention/treatment search. E.g., "pembrolizumab", "cognitive behavioral therapy". Plain words plus AND/OR/NOT. `[ ]` are reserved; `( )` group sub-expressions when matched; `,` acts as AND. | |
| locationQuery | No | Location search — city, state, country, or facility name. Plain words plus AND/OR/NOT. `[ ]` are reserved; `( )` group sub-expressions when matched; `,` acts as AND. | |
| sponsorQuery | No | Sponsor/collaborator name search. Plain words plus AND/OR/NOT. `[ ]` are reserved; `( )` group sub-expressions when matched; `,` acts as AND. | |
| titleQuery | No | Search within study titles and acronyms only. Plain words plus AND/OR/NOT. `[ ]` are reserved; `( )` group sub-expressions when matched; `,` acts as AND. | |
| outcomeQuery | No | Search within outcome measure fields. Plain words plus AND/OR/NOT. `[ ]` are reserved; `( )` group sub-expressions when matched; `,` acts as AND. | |
| statusFilter | No | Filter by study status. Values: RECRUITING, COMPLETED, ACTIVE_NOT_RECRUITING, NOT_YET_RECRUITING, ENROLLING_BY_INVITATION, SUSPENDED, TERMINATED, WITHDRAWN, UNKNOWN, WITHHELD, NO_LONGER_AVAILABLE, AVAILABLE, APPROVED_FOR_MARKETING, TEMPORARILY_NOT_AVAILABLE. | |
| phaseFilter | No | Filter by trial phase. Values: EARLY_PHASE1, PHASE1, PHASE2, PHASE3, PHASE4, NA. | |
| advancedFilter | No | Advanced filter using AREA[FieldName]value syntax. Examples: "AREA[StudyType]INTERVENTIONAL", "AREA[EnrollmentCount]RANGE[100, 1000]", "AREA[Phase]PHASE2 AND AREA[StudyType]INTERVENTIONAL", "(AREA[Phase]PHASE3 OR AREA[Phase]PHASE4) AND AREA[StudyType]INTERVENTIONAL". AND/OR/NOT join complete AREA[FieldName]value expressions; parentheses group them. Call clinicaltrials_get_field_definitions to find AREA[]-compatible field names. | |
| geoFilter | No | Geographic proximity filter. Format: distance(lat,lon,radius). E.g., "distance(47.6062,-122.3321,50mi)" for studies within 50 miles of Seattle. | |
| nctIds | No | Filter to specific NCT IDs for batch lookups. | |
| fields | No | PascalCase leaf names to return; strongly recommended since full records are ~70KB. Common leaves: NCTId, BriefTitle, BriefSummary, OverallStatus, Phase, LeadSponsorName, Condition. Call clinicaltrials_get_field_definitions with a concept query (e.g., "adverse events", "eligibility") to find the exact leaf for any concept. | |
| sort | No | Sort order. Format: FieldName:asc or FieldName:desc. E.g., "LastUpdatePostDate:desc", "EnrollmentCount:desc". Max 2 fields comma-separated. For "largest trials" queries, pair EnrollmentCount:desc with advancedFilter "AREA[StudyType]INTERVENTIONAL" — the top enrollment counts are observational registry/claims studies enrolling tens of millions. Enrollment counts are sponsor-reported and not validated upstream beyond the unknown-enrollment sentinel exclusion. Use clinicaltrials_get_field_definitions to find sortable field names. | |
| pageSize | No | Results per page, 1–200. | |
| pageToken | No | Pagination cursor from a previous response. | |
| countTotal | No | Include total study count in response. Only computed on the first page. | |
| includeUnknownEnrollment | No | Include studies whose EnrollmentCount is the upstream "unknown" sentinel (99999999). Excluded by default — the sentinel pollutes RANGE[N, MAX] queries and EnrollmentCount:desc sorts. Set true for data-quality audits or when targeting unknown-enrollment studies specifically. |
Output Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| studies | Yes | Matching studies. Each entry is a nested ClinicalTrials.gov study record — top-level keys: protocolSection, derivedSection, hasResults, resultsSection, documentSection. Use clinicaltrials_get_field_definitions to explore the schema. | |
| totalCount | No | Total matching studies (first page only when countTotal=true). | |
| nextPageToken | No | Token for the next page. Absent on last page. | |
| requestedFields | No | Echo of the explicit fields parameter — present only when the caller passed fields. Lifts the default truncation cap so all requested leaves render in full. | |
| searchCriteria | No | Echo of active query/filter criteria applied to this search, including sentinelFilterActive when the default unknown-enrollment exclusion is in effect. Present on every response. | |
| notice | No | Recovery guidance when no studies matched — echoes the constraint and suggests how to broaden. Absent on pages with results. |